1. Field of the Invention
The present invention relates to an electrostatic discharge (ESD) protection structure, and more particularly, to an ESD protection structure used on a printed circuit board (PCB).
2. Description of Related Art
No matter in the manufacturing process of an integrated circuit (IC or chip) or after the completion of the manufacture of the chip, an electrostatic discharge (ESD) event is often the main cause of the integrated circuit being damaged. Particularly, in the assembly process of a printed circuit board, any contacts between a human/machine and the printed circuit board may cause the ESD event, thus damaging the chip or elements on the printed circuit board. Therefore, the integrated circuit usually requires an ESD protection function to prevent damages to the integrated circuit caused by an ESD current.
The printed circuit board (PCB) is mainly used to integrate electronic components, circuits, and the integrated circuit for forming an electronic device. In the manufacture process or the assembly process of the printed circuit board, the ESD event easily occurs and damages the integrated circuit of the printed circuit board because the hands of the workers, other printed circuit boards, relevant assembling machines, or testing apparatus may contact the printed circuit board.
The pad and the integrated circuit on the printed circuit board are connected through a metal wire (the metal wire is made of gold, aluminum, or a combination thereof), and therefore, when the ESD event occurs, the ESD current often flows to the inside of the integrated circuit through the pad or a pin on the printed circuit board, thus damaging the integrated circuit. Although the inside of the integrated circuit usually has the ESD protection feature, there are no ESD protection structures/designs disposed between the pad and the integrated circuit to reduce the possible damage to the integrated circuit caused by the ESD event.